In the field of drug preparation for injection or infusion generally two basic problems have to be considered. Firstly, certain demands are made on aseptic conditions so as to avoid contamination of the drug, and, secondly, the drug has to be handled in such a way that drug leakage to the environment is prevented or minimized. By a sterile or aseptic handling of the drug, the risk for transferring bacteria or any other undesired substance to the patient is reduced. By preventing drug leakage to the environment, the exposure of medical and pharmacological staff to hazardous drugs is decreased.
In order to achieve aseptic conditions special safety boxes, cabinets or isolators are being used where the air is filtered through HEPA filters to prevent contamination during preparation of drugs. Ventilated cabinets are also used to reduce uncontrolled leakage to the environment and prevent occupational exposure to possibly hazardous drugs. Such facilities, however, require a lot of space and are associated with relatively high costs. Furthermore, the offered protection can be insufficient and working environment problems due to accidental exposure to drugs, for example cytotoxins, have been reported.
Another solution of the problems mentioned above is to create a so called “closed” or “non-vented” system for handling the drugs during preparation. Such systems exist and enable the preparation to be accomplished without the use of special safety boxes, cabinets or isolators. In such a closed system the drugs are handled isolated from the environment during every single step so as to avoid contamination of the drug and undesired drug leakage to the environment.
A known problem associated with the preparation of drug solutions is the fact that medical bottles or vials normally are made of a non-compressible material, such as glass or plastic. To enable the vial to be drained off, air has to flow into the vial so as to avoid negative pressure in the vial which negative pressure would otherwise counteract or prevent further transportation of liquid from the vial to another receptacle such as syringe.
A system for providing sterilized gas is disclosed in WO 00/35517. A flexible bag containing sterilised gas is provided. The bag has an opening covered by a gas and liquid-impervious membrane which can be punctured by a needle in order to draw the sterilised gas out from the bag for further transportation of the gas to a bottle. A bottle connector is arranged on the current bottle and the bottle connector has a pressure compensation means for receiving gas. By use of a syringe and an injector device provided with a needle the sterilised gas is transferred from the flexible bag to the bottle and to the pressure compensation means arranged on the bottle connector. Thereafter the substance in the bottle can be drawn out from the bottle by means of the injector device while the sterilised gas flows from the pressure compensation means into the bottle.
However, the prior art system described in WO 00/35517 has drawbacks. The system comprises several components to be handled and further the sterilised gas has to be drawn from the flexible bag by means of an injector device provided with a needle, and subsequently transferred to the bottle and the pressure compensation means. Consequently, several manipulations have to be accomplished before the medical substance can be drawn from the bottle.
In WO 02/11794 a system for providing cleaned gas is described. This system works with an injection syringe and an air filter to be attached to a connection nozzle of the syringe. The container of the syringe is charged with air which has been forced through the filter so as to clean the air. Thereafter the air filter is removed and the syringe is connected to a coupling means (injector device) which in turn is connected to a capping means (bottle connector) arranged on a bottle. The capping means has a pressure-equalisation chamber whose volume can vary. The cleaned gas in the syringe is transferred from the syringe to the bottle and to the pressure-equalisation chamber arranged on the capping means. Thereafter the substance in the bottle can be drawn out from the bottle by means of the syringe and the coupling means, while the cleaned gas flows from the pressure-equalisation chamber into the bottle.
Also the prior art system described in WO 02/11794 has drawbacks. The system requires an adapter provided with an air filter being connected to and removed from a syringe in order to fill the pressure-equalisation chamber before the medical substance can be drawn from the bottle. In an alternative embodiment the air filter is fixedly attached to a syringe. However, in such a case a conventional syringe can not be used. In both cases, the cleaned gas has to be drawn from the environment and subsequently transferred to the bottle and the pressure-equalisation chamber before the medical substance can be drawn from the bottle.